Make Callback.Equals() only work when comparing against the same type.

base/base.gyp

 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 101 matching lines @@
 
         # Tests.
         'android/scoped_java_ref_unittest.cc',
         'at_exit_unittest.cc',
         'atomicops_unittest.cc',
         'base64_unittest.cc',
         'bind_unittest.cc',
         'bind_unittest.nc',
         'bits_unittest.cc',
         'callback_unittest.cc',
+        'callback_unittest.nc',
         'command_line_unittest.cc',
         'cpu_unittest.cc',
         'debug/leak_tracker_unittest.cc',
         'debug/stack_trace_unittest.cc',
         'debug/trace_event_unittest.cc',
         'debug/trace_event_win_unittest.cc',
         'dir_reader_posix_unittest.cc',
         'environment_unittest.cc',
         'file_descriptor_shuffle_unittest.cc',
         'file_path_unittest.cc',
@@ skipping 276 matching lines @@
           'msvs_settings': {
             'VCLinkerTool': {
               'SubSystem': '2',         # Set /SUBSYSTEM:WINDOWS
             },
           },
         },
       ],
     }],
   ],
 }